The class of Hamilton's that he attended in the session of 1838-39 was that of Advanced Metaphysics. It so happened that at that time a hot controversy was going on about this very class. The Edinburgh Town Council, who were the patrons of Hamilton's chair, claimed also the right to decide as to what subjects the professor should lecture on, and pronounced Metaphysics to be "an abstruse subject, not generally considered as of any great or permanent utility." But, while this controversy was raging without, within all was calm. "We were quietly engaged"--wrote Cairns twenty years later--"in our discussions as to the existence of the external world while the storm was raging without, and only felt it to be another form of the _non-ego_; while the contrast between the singular gentleness and simplicity of our teacher in his dealings with his pupils, and his more impassioned qualities in controversy, became more remarkable."[1] Hamilton's philosophy may not now command the acceptance that once belonged to it, and that part of it which has been most influential may be put to-day to a use of which he did not dream, and of which he would not have approved, but Hamilton himself--"the black eagle of the desert," as the "Chaldee Manuscript" calls him--was a mighty force. The influence of that vehement and commanding personality on a generation of susceptible young men was deep and far-reaching. He seized and held the minds of his students until they were able to grasp what he had to give them,--until, in spite of the toil and pain it cost them, they were _made_ to grasp it. And he further trained them in habits of mental discipline and intellectual integrity, which were of quite priceless value to them. "I am more indebted to you," wrote Cairns to him in 1848, "for the foundation of my intellectual habits and tastes than to any other person, and shall bear, by the will of the Almighty, the impress of your hand through any future stage of existence." [Footnote 1: _Memoir of Sir W. Hamilton_, p. 231.] Cairns was first in Hamilton's class at the close of the session, and also first in Professor John Wilson's Moral Philosophy Class. "Of the many hundreds of students," Wilson wrote four years later, "whose career I have watched during the last twenty years, not one has given higher promise of excellence than John Cairns; his talents are of the highest order; his attainments in literature, philosophy, and science rare indeed; and his character such as to command universal respect."